Hi folks, I''ve been able to kickstart a number of VMs using the virt-install tool, and so far have had pretty good success. One aspect of these installs has me a bit concerned, though. In most cases, anytime the kickstart needs to do intensive disk activity (such as formatting partitions, or installing all the rpms) there are noticible hangs, which I''m guessing come from some kind of IO wait. The result is that a kickstart which should take < 10 minutes ends up taking a half-hour or so. I''m using pretty standard hardware, Dell 1850s with 2 internal drives. Xvda setup to be 4G, using 500M of memory. Pretty vanilla installs really. Any insight into what might be causing these IO hangs? Thanks, -- Dan
Daniel P. Berrange
2007-Mar-07 21:54 UTC
Re: [Fedora-xen] Kickstart slowness with virt-install
On Wed, Mar 07, 2007 at 01:50:43PM -0800, Hanks, Dan wrote:> Hi folks, > > > > I''ve been able to kickstart a number of VMs using the virt-install tool, > and so far have had pretty good success. One aspect of these installs > has me a bit concerned, though. In most cases, anytime the kickstart > needs to do intensive disk activity (such as formatting partitions, or > installing all the rpms) there are noticible hangs, which I''m guessing > come from some kind of IO wait. The result is that a kickstart which > should take < 10 minutes ends up taking a half-hour or so.What kind of virtual disk image are you using for the guest ? A partition or a file - if the latter is it sparse, or non-sparse. Basically sparse files will be horribly slow because every time the host OS has to extend the sparse file to allocate real blocks it needs to do a journal sync on the host FS. This destroys performance of I/O from the guest until the sparse file is fully-allocated. Regards, Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|